for loop without variable

[Marty]

Mike Meyer wrote:
> On Thu, 10 Jan 2008 22:36:56 -0500 Marty <martyb1 at earthlink.net> wrote:
>> I recently faced a similar issue doing something like this:
>> 
>>      data_out = []
>>      for i in range(len(data_in)):
>>      	data_out.append([])
> 
> More succinctly:
> 
> data_out = []
> for _ in data_in:
>    data_out.append([])
> 
> Or, as has already been pointed out:
> 
> data_out = [[] for _ in data_in]

That's nice.

> 
>> This caused me to wonder why Python does not have a "foreach" statement (and 
>> also why has it not come up in this thread)?  I realize the topic has probably 
>> been beaten to death in earlier thread(s), but does anyone have the short answer?
> 
> But I'm curious - what's the difference between the "foreach" you have
> in mind and the standard python "for"?
> 
>    <mike

For example, I thought the python "equivalent" of perl's foreach might be:

data_out = [[] foreach data_in]

Trying to answer my own question, if it comes down to a choice between a unique 
statement v. the anonymous variable "_", then I guess I can see why Python did 
it this way.